• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.401-412
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• 2003

In this paper, a broadband phase shifter structure using a new switched network was proposed. A new reference network is composed of coupled lines and 45$^{\circ}$open and short stubs, which are shunted at the edge points of a main line, respectively, A delay network is composed of only a standard transmission line. It is possible to design a broadband 180$^{\circ}$phase shifter that phase dispersive characteristics by an impedance ratio R of coupled lines and greater phase dispersive characteristics by characteristic impedances Zm, Zs of a main line and stubs are used together. By considering a structure symmetry, the even and odd mode analysis was performed to obtain theoretical S-parameters of the proposed phase shifter. Also, through computer simulation on the basis of derived equations, design graphs were presented to optimally design a 180$^{\circ}$broadband phase shifter. Design graphs provide the values of characteristic impedances Zm, Zs, and I/O match and phase bandwidths. To verify electrical performances of the broadband phase shifter proposed in this paper, low different 180$^{\circ}$phase shifters, operated at the center frequency 3 GHz were designed and fabricated using design graphs, and were experimented. One of them was designed as a standard Schiffman structure to compare with electrical performances. Measured results of each phase shifter to satisfy simultaneously design conditions of I/O match （VSWR=1.15:1) and maximum phase deviation $({\varepsilon}_{{\Delta}{\phi}}＝{\pm}2^{\circ})$ were well in agreement with corresponding simulation results over impedance match and phase error bandwidths, and showed broadband characteristics.

• Journal of Society of Preventive Korean Medicine
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• v.8 no.1
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• pp.59-74
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• 2004

We have conducted questionnaire and measured serum liver function tests on 153 patients whom have received a treatment at a local Oriental medicine clinic in Seoul from Sept. 1, 2002 to Dec. 31, 2002. Patients were categorized into the groups of control(10), decoction group(41), herbal group(5), western medicine group(45), and the group taking both herbal and western medicines(55) concurrently or separately. This study was conducted to investigate how these treatment methods can affect the liver functions. Following results were obtained : 1) Most of the research subjects were male(l03 individuals) living in large urban area, with drinking habit, highly educated, and with normal marriage. For the treatment history, 45 individuals received western medicine treatment(28.85%), 46 with Oriental medicine (29.49%), and 55 patients(35.26%) experienced both forms of treatment. 2) Measuring SD of serum liver functions for all the research subjects, T-protein was 6.95(0.73)g/dl, 4.07(0.51)g／dl for albumin, 0.44(0.19)mg／dl for T-bilirubin, 23.18(18.68)U／L for ALT, 27.42(27.43)U／L for AST, and 22l.27(64.58)mg／dl for LDH. 3) Among the research subjects with the liver functions outside of normal range were 0.64% for T-protein, 3.21% for T-bilirubin and ALT, 36.62% for AST, 0.64% for LDH, and none for Albumin. 4) Confusion variables which may affect the liver functions such as age, smoking, drinking, occupation, and residence were eliminated in calculation and no significant differences were witnessed between the control and experiment groups. 5) In measuring affects of treatment duration on the liver functions, no statistical significances were shown in multiple regression's ,${\beta}$(SE) values. 6) The values of odd ratio in the experiment groups compared to the control were in the range of $0.26(0.22){\sim}0.62(1.23)$. but T-bilirubin of the group receiving both Oriental and western medicine was 1.47(1.90) which showed statistical increase(p<0.001). 7) Factors affecting the liver functions are drinking volume per round duration of alcohol intake, western medicine treatment, gender, and age difference caused significant influences. 8) 57 individuals with serum liver functions out of normal range were mostly male, living in large urban area, median age of 38.89, with normal marriage, highly educated drinking less than once a week with less than 2 bottles per round, and with prior treatment in either western or Oriental medicine. Summarizing above results, we can carefully deduce that taking herbal medicine (both decoction and pills) or western medicine doesn't cause much affect in the liver functions. But taking two forms of medication simultaneously or altering dosage affect significant increase in the T-bilirubin level, thus one needs to take precaution when taking both. Further research is needed in this field to verify this evidence.

• Korean Journal of Community Nutrition
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• v.27 no.3
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• pp.192-204
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• 2022

Objectives: This study examined the association between dietary behaviors and perceived health status among Korean adolescents from multicultural families. Methods: This cross-sectional study included 2,459 Korean adolescents from multicultural families (aged 13 ~ 18 years) who participated in the 2017 ~ 2019 Korea Youth Risk Behavior Surveys. Information on the sociodemographic variables, dietary behaviors, and lifestyle variables was self-reported using a web-based questionnaire. The dietary behaviors analyzed in this study were the breakfast and food intake frequencies, including fruit, vegetable, milk, fast food, carbonated drink, sweet drink, and high caffeine/energy drinks. The adolescents' health perception was self-rated as healthy, average, or unhealthy. The dietary behaviors associated with health perception were examined using a multiple logistic regression after adjusting for the confounding variables. Results: In this study population, 7.6% of adolescents perceived their health status as unhealthy, and 25.4% perceived it as average. The adolescents who were girls, middle school students, and in households with a low economic status showed significantly higher percentages of poor health perception (P-values < 0.001). Skipping breakfast was significantly associated with a negative health perception. Compared to the adolescents who consumed fruits every day, those who did not consume fruits during the previous week showed a higher odd ratio (OR) for a negative health perception [OR = 2.29, 95% confidence interval (CI) = 1.32-3.97]. The adolescents who frequently consumed carbonated drinks (≥ 5 times/week) perceived their health status as unhealthy relative to those who did not consume carbonated drinks (OR = 2.15, 95% CI = 1.25-3.71). Skipping breakfast was significantly associated with an increased OR for a negative health perception in girls but not in boys. Compared to adolescents with a normal weight, those with overweight/obesity (OR = 1.75, 95% CI = 1.21-2.52) and underweight (OR = 2.19, 95% CI = 1.25-3.82) showed higher ORs for negative health perception. Positive associations of overweight/obesity and underweight with negative health perception were observed in boys but not in girls. Conclusions: Dietary behaviors and weight status were associated with the health perception in Korean adolescents from multicultural families. These findings suggest that nutrition interventions on breakfast intake and healthy food choices for this population might effectively improve their weight and perceived health status.

• Journal of Industrial Convergence
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• v.21 no.5
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• pp.77-85
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• 2023

Suicide is the leading cause of death among Korean adolescents. There is a growing interest in the role of loneliness as a risk factor for suicide ideation and depressive symptoms. However, little is known in the Korean context. This study analyzed a total of 109,796 respondents from the Korea Youth Health Behavior Survey in 2020 and 2021. Multiple logistic regression models were implemented to test the association between loneliness and either of suicidal ideation and depressive mood. Covariates included demographic characteristics, school enrolled, household income, living arrangement, self-rated health, and the number of times treated for violence. Adjusted odd ratio (OR) and 95% confidence intervals (CI) were computed. 12.0% of adolescents reported to have felt lonely frequently and 3.0% always. 11.8% and 26.0% had suicidal ideation and depressive mood, respectively. The prevalence of suicidal ideation was higher in the always-lonely adolescents (52.6%) than in the frequently-lonely adolescents (35.1%). The always-lonely adolescents were nearly 30 times more likely to have suicidal ideation (OR=30.7; 95% CI, 27.1 - 34.8) and to feel depressed (OR=32.5; 95% CI, 29.2 - 36.4) than adolescents who felt never lonely. In conclusion, Loneliness was a major risk factor for suicidal ideation and depressive mood among Korean adolescents. Monitoring and addressing the condition of loneliness may help reduce suicidal ideation and depressive mood.

• 한국체육학회지인문사회과학편
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• v.57 no.5
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• pp.269-279
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• 2018

The purpose of this study is to examine the association between resistance exercise frequency, muscular strength, and health-related quality of life in Korean cancer patients. We performed complex sample general linear model and logistic regression analysis using data from a total of 647 cancer patients in the 2014~2016 Korean National Health and Nutrition Examination Survey (KNHANES). Participants who were participating in resistance exercise 0~1 day per week had lower EQ-5D index (0.852±0.016 vs. 0.890±0.020; p=0.006) and a significantly higher risk of having problems in mobility (Odd ratio[OR]=4.07; 95% confidence interval [CI]=1.31-12.63) compared to those who were participating in resistance exercise ≥ 5 days per week. Participants with low hand-grip strength had lower EQ-5D index (0.850±0.018 vs. 0.911±0.016; p<0.001) and a significantly higher risk of having problems in mobility (OR=4.94, 95% CI=2.14-11.41), usual activities (OR=5.18, 95% CI=1.56-17.14), and pain/discomfort (OR=2.46, 95% CI=1.33-4.55) compared to those with high hand-grip strength. This study showed that resistance exercise frequency and muscular strength were associated with health-related quality of life in Korean cancer patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5660-5667
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• 2014

The aim of this study was to assess the association of metabolic syndrome, metabolic syndrome score (MSS) and pulse pressure (PP) in Korean adults. The study subjects were Korean adults 20 years or older (n=5,889) who participated in the Korea National Health and Nutrition Examination Survey 2012. After adjusting for factors, such as year and gender and BMI, the mean PP increased with increasing MSS (MSS 0, $41.30{\pm}0.34mmHg$ and MSS 1, $42.16{\pm}0.31mmHg$ and MSS 2, $44.73{\pm}0.34mmHg$ and MSS, 3, $46.46{\pm}0.42mmHg$ and MSS 4, $48.62{\pm}0.58mmHg$ and MSS 5, $53.50{\pm}1.05mmHg$), and the mean PP for metabolic syndrome($47.25{\pm}0.34mmHg$) increased in comparison to Non-Metabolic syndrome ($42.77{\pm}0.19mmHg$). When logistic regression analysis was performed, the odds ratio (OR) of Hyper-PP (61> PP) for MSS 0 was 4.49 in MSS 1 (95% confidence interval[CI], 2.68-7.57) and 8.01 in MSS 2 (95% CI, 4.77-13.47) and 11.37 in MSS 3 (95% CI, 6.67-19.35) and 19.69 in MSS 4 (95% CI, 11.20-34.60) and 34.07 in MSS 5 (95% CI, 17.44-66.52), metabolic syndrome was associated with an increased Hyper-PP(OR 4.6, 95% CI, 2.0-10.4). Conclusion. These results suggest that an increase in MSS or metabolic syndrome might increase the pulse pressure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.7
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• pp.868-875
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• 2017

The aim of the present study was to investigate antioxidant nutrient intake and risk of metabolic syndrome based on stress level in rural Korean women. Subject were participants from the Multi-Rural Communities Cohort Study, which was a part of the Korean Genome and Epidemiology Study. According to scores of the Psychosocial Well-Being Index Short-Form, a total of 10,111 subjects were classified into 'low stress group (n=8,015)' from 0 to 26 points and 'high stress group (n=2,096)' above 27 points. Data were collected using self-administered questionnaires, anthropometric measurements, and blood chemical analysis. Dietary nutrient consumption was assessed by a semi-quantitative food frequency questionnaire. High stress group showed lower intake of antioxidant nutrients, such as vitamin A, vitamin C, vitamin E, folate, zinc, and carotene compared to the low stress group. Intake of fruits and vegetable was lower in the high stress group compared to the low stress group. Subjects with high stress showed higher risk of hypertension [odd ratio (OR), 95% confidence interval (CI)=1.226 (1.112~1.351)] and hypertriglyceridemia [OR, 95% CI=1.227 (1.110~1.356)] than subjects with low stress. High stress group had a significantly greater odds ratio for metabolic syndrome compared with the low stress group [OR, 95% CI=1.216 (1.101~1.342]). Thus, the present study suggests that high stress might be associated with low intake of antioxidant nutrients and high risk of metabolic syndrome in rural Korean women.

• Korean Journal of Psychosomatic Medicine
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• v.26 no.1
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• pp.68-75
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• 2018

Objectives : Since pain in cancer patients is an important factor that greatly affects the quality of life and prognosis, many attempts have been actively made to reduce the pain. Despite continuous effort on reducing pain after Endoscopic submucosal dissection (ESD), research has not been done on psychological factors as much as on biological factors affecting pain. The objective of this study is to investigate the psychological factors affecting postoperative pain in gastric tumor patients who underwent gastric ESD. Methods : 91 gastric tumor patients who visited National Health Service Ilsan Hospital in Korean between May 2015 and June 2016, and received ESD were evaluated. Baseline characteristics including sociodemographic factors, anxiety, depression, and resilience were evaluated before the procedure. Multivariate logistic regression was done to analyze factors affecting postoperative pain. Results : The group with high postoperative pain showed lower alcohol consumption and higher depressive symptom scores than the group with low postoperative pain. Also, the group with high postoperative pain showed lower total resilience score with lower subtotal scores in self-control and positive item. Multivariate logistic regression analysis of the postoperative pain showed that patients with lower score in self-control of resilience [odd ratio (OR), 0.911 ; 95% CI, 0.854-0.971, p=0.004) reported more pain after ESD. Conclusions : This study showed that patients with lower self-control ability of resilience felt more pain after ESD. Among the psychological factors evaluated in this study, resilience of an individual seems to have effect on pain.

• Tuberculosis and Respiratory Diseases
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• v.71 no.2
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• pp.120-125
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• 2011

Background: Although the prevalence of pulmonary tuberculosis has progressively decreased all over the world, drug-resistant tuberculosis is major obstacle in treating tuberculosis. This study was performed to examine the current prevalence and risk factors of drug resistant tuberculosis in a single tertiary hospital in Busan, Korea. Methods: We enrolled 367 patients with active pulmonary tuberculosis on a retrospective basis who had undergone mycobacterium culture and drug sensitivity tests between January 2005 and December 2009. We analyzed all clinical and radiographic parameters to find predictors related to drug resistant tuberculosis. Results: At least one incident of drug resistance was found in 75 (20.4%) patients. Isoniazid (18.8%) was the most frequent resistant drug, followed by rifampin (10.9%), ethambutol (7.1%), streptomycin (4.9%), and fluoroquinolone (2.7%). Resistance to second-line drugs was found in 37 (10.1%) patients. Multidrug resistance and extensively drug resistance was evident in 39 (10.6%) and 4 (1.1%) patients, respectively. Using multiple logistic regression analysis, history of previous treatment including relapse (odd ratio [OR], 11.3; 95% confidence interval [CI], 4.92~26.08; p<0.01), treatment failure (OR, 24.1; 95% CI, 5.65~102.79; p<0.01) and an age of below 46 years-old (OR, 3.8; 95% CI, 1.62~8.65; p<0.01) were found to be independent predictors of multidrug resistant tuberculosis. Conclusion: We found that the prevalence of drug resistant tuberculosis was considerably high. A careful consideration for possible drug resistant tuberculosis is warranted in patients with a history of previous treatment or for younger patients.

• Journal of Nutrition and Health
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• v.44 no.5
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• pp.416-427
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• 2011

This study investigated the association among parental socioeconomic level, overweight, and eating habits with diet quality in Korean sixth grade school children. A 3-day dietary survey was conducted, and a questionnaire and anthropometric data were collected from the Korean child obesity cohort (320 boys and 345 girls). The children were classified into two groups (low or high level) based on monthly household income and paternal and maternal education status. Lower maternal education status was associated with a higher risk for overweight in girls (odd ratio, 1.91; 95% confidence interval 1.07-3.44), whereas belonging to a higher socioeconomic group in terms of parental income or parental education level resulted in the consumption of significantly more fruit. Boys did not show significant differences in the intake of most nutrients or diet quality regardless of socioeconomic status. However, girls in the lower socioeconomic group had a lower food habit score (higher frequency of breakfast skipping and ramen noodle consumption), diet quality, and intake of nutrients (carbohydrate, vitamin C, potassium, and fiber) than those in the higher socioeconomic group. Therefore future nutrition policies and interventions should support parents and children with lower socioeconomic status to develop health-related behaviors that may prevent childhood overweight.